<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>el隐式对象</title>
  </head>
  
  <body>
    
    ${pageContext }  <!-- pageContext.findAttribute("name") -->
    
    
    <br/>
    
    <br/>---------------从指定的page域中查找数据------------------------<br/>
    <% 
    	pageContext.setAttribute("name","aaa");  //map
    %>
    ${pageScope.name }
   
   
   	<br/>---------------从request域中获取数据------------------------<br/>
   	<% 
   		request.setAttribute("name","bbb");  //map
   	%>
   	${requestScope.name }
   	
   	<br/>---------------从session域中获取数据------------------------<br/>
   	${sessionScope.user }
   	
   	
   	<br/>--------------获得用于保存请求参数map，并从map中获取数据------------------------<br/>
   	<!-- http://localhost:8080/day12/3.jsp?name=aaa  -->
   	${param.name }  
   	
   	<!-- 此表达式会经常用在数据回显上 -->
   	<form action="${pageContext.request.contextPath }/servlet/RegisterServlet" method="post">
   		<input type="text" name="username" value="${param.username }">
   		<input type="submit" value="注册">
   	</form>
   	
   	<br/>--------------paramValues获得请求参数 //map{"",String[]}------------------------<br/>
   	<!-- http://localhost:8080/day12/3.jsp?like=aaa&like=bbb -->
   	${paramValues.like[0] }  
   	${paramValues.like[1] } 
   	
   	<br/>--------------header获得请求头------------------------<br/>
   	${header.Accept } 
   	${header["Accept-Encoding"] }
   	
   	
   	<br/>--------------获取客户机提交的cookie------------------------<br/>
   	<!-- 从cookie隐式对象中根据名称获取到的是cookie对象,要想获取值，还需要.value -->
   	${cookie.JSESSIONID.value }  //保存所有cookie的map
   	
   	
   	<br/>--------------获取web应用初始化参数------------------------<br/>
   	${initParam.xxx }  //servletContext中用于保存初始化参数的map
   	${initParam.root }
   	
  </body>
</html>
